Research is proposed aimed at increasing our understanding of the nature of the genes determining protein structure in eukaryotes and the control of their expression. Three major systems are to be investigated for their own intrinsic interest and to permit further development and testing of Smithes' DNA-network hypothesis (1970). I. Immunoglobulins: We will investigate the linkage relationship of the genes controlling beta2-microglobulin, immunoglobulin light and heavy chains, and HL-A antigens. II. Hemoglobins: We will continue experiments in mice to determine whether the beta-chains in Diffuse/Single heterozygotes are coordinately synthesized. III. Histones: We will determine whether histones segregate mitotically in a semi-conservative fashion similar to DNA. IV. Radioactive sequencing of protein: We will continue our development of methods for sequencing radioactive proteins.